大三每日总结
软件设计 石家庄铁道大学信息学院
实验 20：备忘录模式
本次实验属于模仿型实验，通过本次实验学生将掌握以下内容：
1、理解备忘录模式的动机，掌握该模式的结构；
2、能够利用备忘录模式解决实际问题。
[实验任务一]：多次撤销
改进课堂上的“用户信息操作撤销”实例，使得系统可以实现多次撤销（可以使用HashMap、ArrayList等集合数据结构实现）。
实验要求：
1.提交源代码；
package BeiWang;
import java.util.ArrayList;
public class Caretaker {
private ArrayList<Memento> mementos = new ArrayList<Memento>();
public Memento getMemento(int i) {
return (Memento) mementos.get(i);
}
public void setMemento(Memento memento) {
mementos.add(memento);
}
}
package BeiWang;
public class Client {
public static void main(String a[]) {
UserInfoDTO user = new UserInfoDTO();
Caretaker taker = new Caretaker();
user.setAccount("刘某");
user.setPassword("20218888");
user.setTelNo("00000000000");
System.out.println("状态一：");
taker.setMemento(user.saveMemento());
user.show();
System.out.println("---------------------------");
user.setPassword("20216666");
user.setTelNo("00000000001");
System.out.println("状态二：");
user.show();
taker.setMemento(user.saveMemento());
System.out.println("---------------------------");
user.setPassword("20214444");
user.setTelNo("00000000002");
System.out.println("状态三：");
user.show();
System.out.println("---------------------------");
System.out.println("回到状态二");
user.restoreMemento(taker.getMemento(1));
user.show();
System.out.println("---------------------------");
System.out.println("回到状态一");
user.restoreMemento(taker.getMemento(0));
user.show();
System.out.println("---------------------------");
}
}
package BeiWang;
public class Memento {
private String account;
private String password;
private String telNo;
public Memento(String account, String password, String telNo) {
this.account = account;
this.password = password;
this.telNo = telNo;
}
public String getAccount() {
return account;
}
public void setAccount(String account) {
this.account = account;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public String getTelNo() {
return telNo;
}
public void setTelNo(String telNo) {
this.telNo = telNo;
}
}
package BeiWang;
public class UserInfoDTO {
private String account;
private String password;
private String telNo;
public String getAccount() {
return account;
}
public void setAccount(String account) {
this.account = account;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public String getTelNo() {
return telNo;
}
public void setTelNo(String telNo) {
this.telNo = telNo;
}
public Memento saveMemento() {
return new Memento(account, password, telNo);
}
public void restoreMemento(Memento memento) {
this.account = memento.getAccount();
this.password = memento.getPassword();
this.telNo = memento.getTelNo();
}
public void show() {
System.out.println("Account:" + this.account);
System.out.println("Password:" + this.password);
System.out.println("TelNo:" + this.telNo);
}
}
2. 注意编程规范。
